Traditional products for the treatment or prevention of insect or parasite infestation of animals include shampoo treatments, insecticidal collars, orally ingested treatments, compositions designed to treat an animal's environment, spot-on treatments, and the like. Different treatment forms offer unique benefits and drawbacks; however, the majority offer substantial disadvantages. For instance, shampoo treatments require that the treatment be applied over the entire surface of the animal and subsequently rinsed off, which is typically unpleasant for both the animal and the owner and only provides a short-term, transient treatment. Insecticidal collars require the animal to physically wear the collar for a period of time often lasting several months, which is uncomfortable and burdensome to the animal. Additional, treatments administered orally tend to increase the possibility of side effect and are more difficult to administer to the animal. Alternatively, treatment of the animal's surroundings and habitat is often undesirable due to the fact that the treatment may cause discoloration of furniture, carpet, bedding, etc., and may also produce unpleasant odors. Thus, it is desirable to have a spot-on treatment that can be applied to the animal in smaller portions, while maintaining treatment efficacy across the entire body surface of the animal.
Spot-on compositions that have been previously developed incorporate a multitude of pesticide agents. Common agents include arylpyrazole derivatives, insect growth regulators, pyrethroids, nodulisporic acid derivatives, neonicotinoids, formamides, avermectins, and the like. All of the compounds listed herein have different mechanisms of action, and accordingly treat and prevent infestation in different manners. Consequently, the various compounds also have a variety of different adverse effects associated with treatment. The various agents may be combined in a variety of concentrations. Generally, higher concentrations of the active components result in higher pest kill rates, and more successful treatments; however, the use of higher concentrations of the active components are more expensive to make and result in a greater likelihood that the animal will suffer adverse effects from treatment. Adverse effects of treatments include skin discoloration, local hair loss, itching, redness, excessive salivation, and in certain cases, neurotoxicity.
The spot-on treatments known within the art generally have a prolonged period of action before the active ingredient(s) effectively eliminates the target pest. For instance, insect growth regulators (i.e. juvenile hormone mimetics) exterminate target pests by effectively inhibiting the development of immature pests, so that they are not able to reproduce. Even though the insect growth regulators are effective in ultimately controlling the pest infestation, additional time is required to kill all pests, which leads to additional time in which the animal host, as well as all other animals and humans, must suffer the effects of the infestation. Even quick-acting agents, such as the arylpyrazole derivative known as fipronil, which causes hyperexcitation of the pest leading to its death, have a prolonged onset of action. Generally, it may take multiple hours for quick-acting agents to provide symptomatic relief to the host animal.
Therefore, given the limitations of the prior art, it would be desirable to have a spot-on pesticide treatment that utilizes low concentrations of known chemicals so as to minimize the risk of adverse effects, has a high pest kill rate, and has an improved kill rate, preferably within the first hour of treatment.